[36 minutes] Two pipes can fill a tank in 20 minutes and 30 minutes respectively. Both pipes are opened simultane

For Competitive Exams

Two pipes can fill a tank in 20 minutes and 30 minutes respectively. Both pipes are opened simultaneously. When the tank should have been full, it is found that the waste pipe was open.Then the waste pipe was closed and in another 4 minutes, the tank was full. In what time would the waste pipe empty it.

35 minutes

36 minutes

37 minutes

38 minutes

Explanation:
The first two pipes together can fill the tank in $\dfrac{20×30}{20+30}$=12 minutes.
Therefore, quantity filled by first pipe and second pipe together in 4 minutes is equal to quantity emptied by waste pipe in 12 minutes.
i.e., quantity filled by first pipe and second pipe together in 12 minutes is equal to quantity emptied by waste pipe in 36 minutes.
i.e., waste pipe can empty the tank in 36 minutes.

Additional Questions

A and B can fill a cistern in 7.5 minutes and 5 minutes respectively and C can carry off 14litres per minute. If the cistern is already full and all the three pipes are opened, then it is emptied in 1 hour. How many litres can it hold? Pipe A in	Answer
Pipes A and B can fill a cistern in 15 hours together. But if these pipes operate separately A takes 40 hours less than B to fill the tank. In how many hours the pipe A will fill the cistern working alone?	Answer
Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?	Answer
Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in:	Answer
One pipe can fill a tank three times as fast as another pipe. If together the two pipes can fill the tank in 36 minutes, then the slower pipe alone will be able to fill the tank in:	Answer
Two pipes A and B can separately fill a cistern in 40 minutes and 30 minutes respectively. There is a third pipe in the bottom of the cistern to empty it. If all the three pipes are simultaneously opened, then the cistern is full in 20 minutes. In how much time, the third pipe alone can empty the cistern?	Answer
Two pipes P1 and P2 can separately fill a cistern in 30 and 20 minutes respectively and a waste pipe P3 can carry off 11 litres per minute. If all the pipes are opened when the cistern is full,it is emptied in 42 hours. How many litres does the cistern hold?	Answer
A tap takes 36 hours extra to fill a tank due to a leakage equivalent to half of its inflow. The inflow can fill in how many hours?	Answer
A tap takes 36 hours extra to fill a tank due to a leakage equivalent to half of its inflow. The inflow can fill in how many hours?One pipe can fill a tank three times as fast as another pipe. If together, the two pipes can fill the tank in 36 minutes, then the faster pipe alone will be able to fill the tank in	Answer
Two pipes can fill a tank in 20 minutes and 30 minutes respectively. Both pipes are opened simultaneously. When the tank should have been full, it is found that the waste pipe was open.Then the waste pipe was closed and in another 4 minutes, the tank was full. In what time would the waste pipe empty it.	Answer

Share with Friends